Creates a new oeisstream.
Passing any of the specified parameters
to the one of the non-default constructors is equivalent to
creating a new oeisstream with the default
constructor and then
calling the appropriate oeisstream.set method
on that stream.

If the copy constructor is used, the newly created oeisstream will
read from the same data string as the stream being copied from. If
the ‘copy’ parameter was set to true on the stream being copied from,
the new stream will create its own local copy to read from,
otherwise it will just point to the same place in memory as the
original stream. In addition, the newly constructed stream’s
reading pointer will be set to the same location as the one in the
stream being copied from.

Regardless of whether or not a local copy is made, the stream takes
no responsibility for the management of the original input source’s
memory.

Clears the current stream and sets the input source of this stream
to be the same as the one in the assigned stream. If the copy
parameter was set to true on the assigned stream, the stream will
create its own local copy to read from, otherwise it will just
point to the same place in memory as the assigned stream. In
addition, the stream’s reading pointer will be set to the same
location as the one in the assigned stream.

Clears the association with input source associated with this
stream. If the copy parameter was set to false when this stream was
assigned or constructed, no changes will be made to the original
data source.

Sets the input source of this stream based on the specified
parameters. The buffer parameter specifies the data string to be
used as the input source. If the char* constructors are used, the
length of the input buffer must be specified as well as whether or
not a local copy of the buffer should be made and used as the input
source. If the std::string method is used, a local copy of the
input string will be made and used as the input source.

Regardless of whether or not a local copy is made, the stream takes
no responsibility for the management of the original input source’s
memory.